Ibrahim al-Asiri

Con Coughlin, in the Telegraph, profiles the al-Qaeda bomb-maker generally regarded as the terrorist most likely to devise a way to evade Western security and bomb a civilian target.

He has been described as the world’s most dangerous terrorist. The ingenious explosive devices designed by Ibrahim al-Asiri explain why intelligence officials on both sides of the Atlantic have raised fresh concerns about airport security.

The 32-year-old, originally from Saudi Arabia, is a leading figure in the Yemeni-based al-Qaeda in the Arabian Peninsula, and has been the brains behind a number of high-profile aircraft bomb plots.

These have included the so-called “underpants bomber” who tried to blow up a plane as it approached Detroit airport on Christmas Day 2009, and the ink cartridge bombs uncovered at Dubai and East Midlands airport the following year.

British explosives experts had examined a consignment of suspect printers without locating the device concealed in one of the ink cartridges, and they were about to be loaded on to a cargo flight to the US when a last-minute tip-off from Dubai, where the authorities had discovered a similar device, averted disaster.

Asiri’s fanaticism is such that he even blew up his own brother, Abdullah, in a failed attempt to assassinate Saudi Arabia’s head of security. Asiri built a device that was concealed in his brother’s rectum and detonated by remote control from a mobile phone. Abdullah was killed instantly, although the Saudi official suffered only minor injuries.

Intelligence officials believe Asiri is now trying to develop a device that will escape detection by even the most sophisticated scanning equipment. His latest technique is to use an explosive known as pentaerythritol tetranitrate, or PETN, which has no odour, and therefore foils sniffer dogs and X-ray machines.

Not surprisingly the threat he poses has made him one of Washington’s most high-value targets, with President Barack Obama putting a $5 million (£3 million) price on his head.